Instrument panel lighting



Feb. 25, 1958 J, M ROPER 2,824,954

INSTRUMENT PANEL LIQHTING Filed June 28, 1954 'Y' l j I O 55 l+ "if "ffINVENTOR United States Patent INSTRUlVIENI' PANEL LIGHTING John M.Roper, Washington, D. C., assignor to Grimes Manufacturing Company,Urbana, Ohio, a corporation of Ohio Application June 28, 1954, SerialNo. 439,796

9 Claims. (Cl. 24U-8.16)

This invention relates to instrument panels or dials and to means forilluminating them so that the indicia or legends carried thereon may beread at night or under other circumstances involving the absence ofnatural lighting.

More particularly, the invention has reference to the illumination ofthe indicia applied to or incorporated inY the panels by lighttransmitted through the material of which the panel is composed, andfrom a light source carried by the panel and located substantially inthe planeV thereof, whereby the rays of light are transmitted edgewiseof the body ofthe panel.

The general object of the invention is to provide a novel and improvedsystem of illumination of the class described, which will enhance theefficiency of the panel lighting, increase the compactness of theinstrument assembly, widen the versatility of location of the lightsources, and generally improve the provisions for illumination of thedials, instrument and console panels, and otherrindicia bearingsurfaces, such as those to be found in the cockpits of aircraft, onshipboard, or elsewhere.

Although the edge illumination of plastic panel lighting' systems hasbeen in use for some time, diculty and inconvenience have beenexperienced in the matter of the awkward rearward projection from thepanel of parts of the lighting installation and the interference of suchprojecting parts with the instruments or instrument casings disposedbehind the panels.

It is well known that space in the cockpit of an aircraft is at apremium and the various instruments, housings, and panels must becrowded as close together as possible, and the various fastenings,electrical connections and accessories must occupy a minimum of spaceand not interfere with the compact assemblage of the controls.Heretofore, the manufacturers of control instruments for aircraft had totake into consideration in the planning of the instruments and theirhousings and casings, the accommodation of the rearwardly projectingparts of the superimposed instrument or console panel, and theinstrument boxes and the panels had to be designed to intert andaccommodate irregularities of construction of this nature. The presentinvention enables the manufacture of the console equipment and themanufacture of the plastic plate panel and the locating of the lightingfixtures therein to be planned independently, the one without referenceto any possibility of conict with the other.

Another advantage afforded by the present invention is the more elcientVentilating and cooling of the lamp which is the source of illuminationwithin the panel, and the elimination of any metallic or other opaqueparts surrounding the lamp within the contines of the boundary surfacesof the plastic light transmitting panel plate.

Another feature of the invention resides in the utilization of thecovering cap of the lighting xture on the outer face of the panel as oneof the ground connections, so that inadvertent short-circuits of thelighting system through switch handles or other equipment located nearthe lighting fixture, are obviated.

Other objects and features of novelty, including the installation andarrangement of circuit leads to the lighting fixtures, again avoidingprojection from the rear face of the panel, will be apparent from thefollowing specication when read in connection with the accompanyingdrawings in which certain embodiments of the invention are illustratedby way of example.

In the drawings:

Figure l is a view in front elevation of a portion of an illuminatedinstrument or console panel embodying the principles of the invention;

Figure 2 is a vertical sectional view taken on line 2-2 of Figure 1;

Figure 3 is a horizontal sectional view taken atright angles tothesection of Figure 2;

Figure 4 is a view in perspective of a shell forming one of theconductor elements of the lamp mounting; l

Figure 5 is a fragmentary sectional View taken on line 5 5 of Figure l,and showing the embedment of a conductor in the surface of the lightconducting panel; and

Figure 6 is a fragmentary detail view in section similar to that of thelower central portion of Figure 2, but showing an alternativearrangement of the conductor terminal.

In Figure 1 of the drawings there is illustrated an exemplaryarrangement of a small section of an instrument or console panel for anaircraft or the like.

This panel section is indicated generally by the reference numeral 10and as in some conventional constructions, it is provided with cutouts11 for the application of' standard securing or fastening elements whichserve to attach the panel to an underlying supporting plate 12, por-Vtions of which are shown within the confines of the cutouts 11. Thisplate 12 may in practice be the front plate of casings or housings forthe instruments or equipment behind the lighting panel. In theparticular suggestive embodiment shown in Figure 1, the portions 12 maybe projecting flanges from an instrument box, the boundaries of whichbox are indicated by the broken lines 13.

However, the present invention in its general aspects is applicable to awide variety of instrument and console installations, whether in thecockpit of an aircraft, on the bridge of a ship, or/in any otherinstallation where excellent controlled lighting is needed. The novelarrangement is particularly useful in situations Where the lightingpanel 10 is applied to the front wall 12 of the instrument box and inclose contact therewith.

The particular panel used for illustrative purposes in the drawings isprovided with three control knobs 15 with their associated markers orindicator lines 16 and printed legends 17. The markings 16 and thelegends 17 are illuminated from within the panel 10 which is made oflight conducting material which may be selected from well-known plasticsor other materials having the property of conducting or transmittinglight. The major portion of the surface of the panel where the markingsand legends do not occur is coated with an opaque material preferablyhaving a black surface.

As sources of illumination for transmitting light through the body ofthe panel 10 to the legends and markings which are to be illuminated,there are provided the lighting fixtures indicated generally by thereference characters 2l). These lighting fixtures are disposed atstrategic points upon the panel so as to be uniformly distributed withrespect to the legends to be illuminated. As these lights are sodesigned as to not project into the control box beyond the lightingpanel, they can be located as desired without regard to the arrangementof equipment in the control box. The two lamp assemblies 26 shown inFigure 1 are symmetrically disposed with respect to the markings for thethree switches 15.

The lamp installations 20 will now be described ,in

Patented Feb. 25, s

areV thus inconspicuous, avoid interference -with legends andinstruments on the panel plate, and never enter the plate to any depthsufficient to interfere with the perfect transmission of light edgewisethrough the panel.

In the embodiment shown in Figure 2 of the drawings the wires are raisedslightly from the surface of the plate 25 at the points where thelighting fixture 20 occurs and the finger terminals 5S and 60 areextended along the surface of the plate 25 and are wrapped around theraised portions of the wires which pass through grooves in the plasticrings 31. These grooves may be either pre-formed or the wires may againbe used to embed themselves in the plastic by the use of heat.

In another embodiment of the invention as suggested in Figure 6, thesurface of the plate 25 may be notched out and the ends of the prongs 55and 60 projected into the notches and then bent around the conductingwires in their embedded position within the surface of the plate 25.

It Will be seen that by the provisions of this invention all projectionsfrom the rear face of the panel have been eliminated and thus the panelmay be applied against the instrument casings without the necessity ofindenting the casings or designing them to avoid the contacts whichmight project from the panel. There are also no metal portions of thelighting fixture projecting into the plastic plate 25 to interfere withthe light distribution.

Various changes and modifications may be made in the embodimentsillustrated and described herein without departing from the scope of theinvention as dened by theV following claims.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

l. An instrument console panel installation comprising, in combination,a panel plate composed of light transmitting material, opaque outerlayers on both sides of said panel plate, apertures in the outer layeron the forward surface of said panel, said apertures defining indicia,an aperture in said panel plate, a cylindrical plastic bushing securedin said aperture and having an annular rib engaging one surface of saidpanel plate, a metal sleeve located within said bushing and having anger terminal extending radially through said bushing between said riband the surface of said plate, a lamp secured in said sleeve, said lampcomprising a bulb, a cylindrical cap which defines one electricalcontact for said bulb and a central base contact extending from saidcap, said metal sleeve defining another electrical contact for saidbulb, a metallic shell engaging the portion of said bushing extendingfrom said rib, said shell having a nger terminal thereon and having aninternal annular groove interlocked with said rib, said shell beingthreaded on its outer periphery, and a plastic annular ring encirclingsaid bushing in the region of the forward surface of said panel plateand engaging the f finger terminal of said metal sleeve and the fingerterminal of said metal shell, said cap having an internally threadedtubular portion, said internally threaded tubular portion engaging theouter periphery of said metal shell, one of said outer layers extendingaround the outer periphery of said annular plastic ring, said tubularportion engaging said outer layer extension to provide a waterproofseal.

2. An instrument console panel installation in accordance with claim 1wherein said body plate is coated on both sides with thin layers oftranslucent plastic and wherein a pair of conductors engage said fingerterminals in the forward plane of said panel plate.

3. An instrument console panel installation in accordance with claim 2wherein said conductors are imbedded in the forward surface of saidpanel plate and said finger terminals each extend around one of saidconductors.

4. An instrument console panel installation comprising a panel pgatecomposed of light transmitting material, and having a rear surfaceadapted to come into close proximity totinstrumeuis or mechanisms to becontrolled,

and a front surface bearing indicia adapted to serve asV reference mediafor controlling devices movably mounted adjacent said panel, saidindicia adapted to be illuminated by light transmitted edgewise throughthe panel plate, a lighting fixture and conductors leading there.

from, said lighting fixtures and said conductors being carried by saidpanel plate and supported and positioned substantially forwardly Vof theplane of the extreme rear surface of said panel, said panel plate havingan opening therein, said lighting fixture including a lamp, a base andsocket assembly secured to the edges of said opening' with the lampwithin the confines of the planes of the front andrear surfaces of saidplate and the base and socket projecting forwardly of the plate, saidsocket having an annular projection thereon terminals extending fromsaid assembly approximately at the plane of the forward surface of theplate, said conductors being connected to said terminals and disposed nsubstantially parallel and coplanar'relationship along the front surfaceof said plate, a covering and sealing ring surrounding the projectingportionsof said base and socket assembly, covering said terminals andconductor connections, and secured to said plate, the annular projectionof said socket assembly being threaded and a threaded cap applied tosaid assembly and screwed down upon said sealing ring, and a coating'ofcovering material applied to the front surface of said panel plate,covering said conductors and said sealing coating, which ring isattached-to said ring about the margin of said opening and contacted bysaid threaded cap.

5. ln combination a translucent instrument panel having indicia thereon,an installation supported by and positioned substantially forwardy ofthe plane of the extreme rear surface of said panel, a miniature lampincluding a bulb and a cylindrical base providing one electrical contactand an axially projecting post providing the other electrical contact, ametallic sleeve fitted closely about said base and having a terminalfinger projecting radially therefrom at a point intermediate the ends ofthe lamp, a cylindrical tubular translucent member surrounding saidsleeve and extending axially substantially the full length of the lampand adapted to be fixed within an opening in the instrument panel, ametallic shell surrounding that portion of said cylindrical member whichenvelops the base of the lamp, the portion of the translucentcylindrical member which surrounds the bulb of the lamp being clear ofany opaque envelopments, said outer shell being provided with a radiallyprojecting terminal finger and being externally threaded, the firstnamed terminal finger extending from the middle sleeve which surroundsthe lamp base and projecting through the wall of the cylindricaltranslucent member, and a metal internally threaded cap screwed downupon said metal shell and having an electrical contact engaging saidterminal post of the lamp whereby when said xture terminals areconnected with a source of current, the current fiows from the firstnamed finger through the metal sleeve, the cylindrical portion of thelamp base, the lamp filament, the contact post, the screw cap, the metalshell and the other terminal finger extending from said shell.

6. An instrument console panel installation in accordance with claim 5wherein the terminal nger extending from the outer metallic shell isconnected to ground so that the exposed metal screw cap is groundedWhereby the danger of short circuiting by inadvertent contact betweenother conductors and the cap is obviated.

7. An instrument console panel installation comprising a translucentsupporting panel, opaque outer layers on both sides of said panel, acylindrical tubular translucent member mounted in said panel, anexternally threaded metallic shell surrounding said tubular member forapproximately half its length from one end thereof having a fingerterminal thereon, a metallic sleeve disposed

